Method and apparatus for sterilizer tests and control



Sept. 30, 1958 J. w. BEAKLEY ET AL 2,854,384

METHOD AND APPARATUS FOR STERILIZER TESTS AND CONTROL Filed Sept. 17, 1956 ilnited States Patent METHOD AND APPARATUS FOR STERILIZER TESTS AND CONTROL John W. Beakley and Willard W. Dean, Phoenix, Ariz.

Application September 17, 1956, Serial No. 610,261

4 Claims. (Cl. 195-54) This invention concerns a. method and apparatus for sterilizer tests and control.

One of the objects of the invention is to provide a method and means for checking the efficiency and sufiiciency of sterilization process as applied to hospital items, needs and wants and a means and apparatus for positively determining the presence or absence of live micro-organ-- isms following sterilization in sterilizing apparatus;

Another object is to provide a method and apparatus for sterilizing wherein there is no need for handling any of the apparatus or test elements in a manner likely to contaminate them and wherein all critical objects used in the test are contained in a sealed tube or ampule;

Still another object of the invention is to provide a method for testing sterilization of various objects wherein it is unnecessary to handle either the test samples of microorganisms or the culture media apart from a single ampule in which all the ingredients necessary for the test are contained;

Still another object is to provide a test ampule containing a sterile culture media at the bottom, a meltable separating plug above this media, a test liquid, or a cap-' sule containing test liquid which contains spores or microorganisms (at the top of the ampules), and a sealed top enclosure for the ampule.

Other objects will appear hereinafter.

We attain the foregoing objects by means of the process hereinafter described and the apparatus illustrated in the accompanying drawing wherein- Figure 1 is a side elevation of an ampule containing the necessary elements to carry out our sterilization test process; and

Figure 2 is a side elevation of an ampule after it has been subjected to the heat of sterilization.

Similar numerals refer to similar parts in the several views.

Heretofore it has been a common practice to include certain capsules, tubes or absorbent strips containing live bacteria, spores, or micro-organisms with various objects to be sterilized. After sterilization these substances or strips were placed in a culture media and this mix placed in a warming oven to develop the micro-organisms, or the like, in the culture. The culture was thereafter tested and examined to determine if any of the micro-organisms survived the sterilization and grew in the culture. This process required the handling of the objects containing the micro-organisms and also a direct handling of the container holding the sterile culture media. Such a process is time-consuming, and is subject to inaccuracy due to possible contamination of either the test objects or the culture itself.

In carrying out our process, we provide an ampule 2 which has a closed "bottom 3 and may be closed at the top 4. In the bottom portion of the ampule, before sealing, we place a sterile, clear culture media which may be any one of the well-known fluids in which micro-organisms will grow rapidly at a proper temperature. Above 2,854,384 Patented Sept. 30, 1958 ICE this culture media we place a meltable plug 7 of insoluble material which seals the culture media 6 from the substance above it. In the upper part of the ampule and above the meltable plug we place a liquid 8 containing spores or micro-organisms used in various well-known sterilization tests; These may be, for example, Bacillus subtilis, Clostridium sporogenes, or Bacillus stear0thermophilus. The top 4 of the ampule is then sealed in any well-known manner.

Variation of the above may include the use of dry spores or the inclusion of the various test micro-organisms in separate meltable capsules 8a and 9 so that, if desired, more than one type of micro-organism may be included in the ampule. In Figure 1 this variation is shown, al-

though it is to be understoood that the ampule may be used with the liquid 8 only, if desired.

The meltable plug may be made of paraffin wax, beeswax combined with. other waxes, orv other substances which will melt and become fluid at the temperatures ordinarly used or required for sterilization.

In use, the ampule is included in approximately the center of any substancesor objects that are to be sterilized. The exact positioning of the ampule is not critical, except that it should be placed so that it attains the lowest temperature of the sterilizer. The substances or articles to be sterilized are then placed in the sterilizer and subjected to heat for the time necessary to attain sterility according to usual practices. The articles are then withdrawn from the sterlizer and the ampule is placed in a culture oven and maintained at a temperature sufiicient to cause the growth of the bacteria or micro-organisms, previously contained in the upper part of the ampule, in the culture media which was previously in the lower part of the ampule. During the period of sterilization the meltable plug 7 which originally separated these two substances is melted, and the liquids in the upper and lower parts of the ampule mix. If the micro-organisms in the substances 8 or 9 have not been completely killed by the sterilization, they will grow and multiply during the heating period in the culturing oven and their presence can be detected by cloudiness imparted to the' otherwise clear culture media 6 or by any other well-known methods.

From the foregoing it Will be understood that the culture media 6 in the bottom portion of the ampule must be prepared so as to be sterile when contained in the ampule, and must be filtered so that it is entirely clear; Likewise, the substance containing the bacilli or microorganisms must be filtered and rendered normally clear.

From the foregoing it will be understood that we have provided a closed container, termed an ampule, which contains all the necessary ingredients to perform the tests required to determine sterility, and that this container may be sealed after preparation and stored in any ordinary manner common to material of this type. In performing the process it is not necessary to break the ampule or expose either the culture media or the test organisms to the air so that there is a possibility of contamination. An ampule prepared in this manner eliminates handling of both substances separately by the laboratory technician and shortens the labor necessary for the test by eliminating the necessity for separate containers for the culture media and for the micro-organisms.

Therefore, in addition to saving the time heretofore consumed in making these tests, the process and apparatus above described make it possible to make the tests more accurate, and lessen thechances of contamination from outside sources.

We claim:

1. In apparatus for testing sterilization of objects by heat, a sealed ampule tube adapted to be placed with objects to be sterilized in a sterilizing oven, said tube mally separating said fluid and media, and disposed so that when melted saidfluid and media will 2. Apparatus for testing the sufiiciency of sterilization of objects by heat, composed of a closed ampul'e tube,

adapted to be placed'in a sterilizing oven, a fluid culture medium contained in saidtube, a solution containing-live spores of micro-organisms, and a plug meltable at'tlir mal conditions of sterilization, normallyseparating said spores from said culture medium and arranged so that culture medium will mix with said spores when said plug is melted.

3. Apparatus for testing the suflicien'cy of sterilization of objects by heat, composed of a closed ampule tube, adapted to be placed in a sterilizing oven, containing a fluid culture medium within said tube, a solution containing live spores of micro-organisms contained within said tube, and a plug of meltable material meltable below the thermal conditions of sterilization and above normal working and handling temperatures to which the tube is exposed, normally separating said spores from said culture medium and arranged so that culture medium will mix with said spores when said plug is melted.

4. Apparatus for testing the sufliciency of sterilization of objects by heat composed of a sealed a'mpule tube,

adapted to be placed in a sterilizing oven, a fluid culture medium for micro-organisms within one end of said ampule tube, a fluid containing live spores of Bacillus subtilis, within the opposite end portion of said tube, and a plug of insoluble, meltable, sterile material within said tube, normally separating said two fluids, meltable at the temperature of sterilization, and disposed so that when melted said two fluids will mix.

References Cited in the file of this patent UNITED STATES PATENTS Clark Oct. 25, 1949 OTHER REFERENCES 

1. IN APPARATUS FOR TESTING STERILIZATION OF OBJECTS BY HEAT, A SEALED AMPULE TUBE ADAPTED TO BE PLACED WITH OBJECTS TO BE STERILIZED IN A STERILIZING OVEN, SAID TUBE CONTAINING A CLEAR FLUID CULTURE MEDIA, A CLEAR MEDIA CONTAINING LIVE MICRO-ORGANISMS, AND A PLUG OF A SUBSTANCE MELTABLE AT THE TEMPERATURE OF STERILIZATION NORMALLY SEPARATING SAID FLUID AND MEDIA, AND DISPOSED SO THAT WHEN MELTED SAID FLUID AND MEDIA WILL MIX. 